Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the read-only/idempotent annotations, the description discloses the three-item cap, that unpublished documents are silently dropped, that an empty result mirrors get_document's not-found answer, and that clients without card support receive a text answer. These are non-obvious behaviors an agent could not infer from structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the use case, then the input, then the fallback behavior, then the negative guidance. It is dense but every sentence carries distinct information; only the text-fallback sentence is mildly tangential.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers trigger, input source, item cap, filtering of unpublished documents, empty-result semantics, and client-capability fallback. With an output schema present, no further explanation of return values is required.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: the ids come from the id of each card, and the three-item limit is restated as a practical constraint. The UUID format itself is left to the schema, which is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('shows up to three of them as a carousel of cards') plus what each card contains. It also distinguishes itself from get_document and search_documents by naming both siblings directly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit trigger ('when a person wants to see documents that search_documents or get_document returned') and an explicit exclusion ('Do not use it to find documents: call search_documents for that'). The alternative tool and the condition that selects it are both stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.